The present invention relates to an image display device having self-luminous elements thereon, such as EL (Electroluminescence) elements, organic EL elements, etc., and a driving method of the same.
The self-luminous element typified by the EL element, organic EL element, etc. has a property such that a luminance of the element is proportional to a current amount flown into the self-luminous element. Therefore, a gradation display can be realized by controlling the current amount flown into the element. A plurality of self-luminous elements as described above are arranged, so that a display device can be realized.
On the other hand, a touch panel has been used as a technique for applying an input function to a display device. However, there arises a problem such as degradation for a display quality, for example, a luminescence etc., and cost increase, since the touch panel is laminated on the surface of display device.
As for a means of solving the problem, U.S. Pat. No. 7,205,988 has disclosed a technique to give a display device an input function by housing an optical sensor in the display device, without laminating a device such as a touch panel.
However, the technique disclosed in U.S. Pat. No. 7,205,988 requires to additionally form a photodiode on a glass board in a display area of a liquid-crystal display, separately or other than display elements. This causes a transmission factor to make lowered. Even in the case where the technique is applied to the foregoing self-luminous display device, a power consumption could be increased, and a life of the display device could also be lowered, since an aperture ratio is made lowered.